20 Better transport

Modern vehicle technology can reduce climate change emissions without changing the look, feel or performance that owners have come to expect.

California Air Resources Board

Roughly one third of our energy goes into transportation. Can technology
deliver a reduction in consumption? In this chapter we explore options for
achieving two goals: to deliver the biggest possible reduction in transport’s
energy use, and to eliminate fossil fuel use in transport.

Transport featured in three of our consumption chapters: Chapter 3
(cars), Chapter 5 (planes), and Chapter 15 (road freight and sea freight).
So there are two sorts of transport to address: passenger transport, and
freight. Our unit of passenger transport is the passenger-kilometre (p-km).
If a car carries one person a distance of 100 km, it delivers 100 p-km of
transportation. If it carries four people the same distance, it has delivered
400 p-km. Similarly our unit of freight transport is the ton-km (t-km). If a
truck carries 5 t of cargo a distance of 100 km then it has delivered 500 t-km
of freight-transport. We’ll measure the energy consumption of passenger
transport in “kWh per 100 passenger-kilometres,” and the energy con-
sumption of freight in “kWh per ton-km.” Notice that these measures are
the other way up compared to “miles per gallon”: whereas we like vehicles
to deliver many miles per gallon, we want energy-consumption to be few
kWh per 100 p-km.

We’ll start this chapter by discussing how to reduce the energy con-
sumption of surface transport. To understand how to reduce energy con-
sumption, we need to understand where the energy is going in surface
transport. Here are the three key concepts, which are explained in more
detail in Technical Chapter A.

In short-distance travel with lots of starting and stopping, the energy
mainly goes into speeding up the vehicle and its contents. Key strate-
gies for consuming less in this sort of transportation are therefore toweigh less, and to go further between stops. Regenerative braking,
which captures energy when slowing down, may help too. In addition, it
helps to move slower, and to move less.

In long-distance travel at steady speed, by train or automobile, most
of the energy goes into making air swirl around, because you only
have to accelerate the vehicle once. The key strategies for consuming
less in this sort of transportation are therefore to move slower, and tomove less, and to use long, thin vehicles.

In all forms of travel, there’s an energy-conversion chain, which takes
energy in some sort of fuel and uses some of it to push the vehicle

Figure 20.1. This chapter’s starting point: an urban luxury tractor. The average UK car has a fuel consumption of 33 miles per gallon, which corresponds to an energy consumption of 80 kWh per 100 km. Can we do better?